This request is for funds to purchase a basic single photon Nikon A1 confocal microscope with two GaSP detectors. This instrument will be housed within the Center for Biologic Imaging (CBI) at the University of Pittsburgh School of Medicine. The mandate of this core facility is to provide access to a full range of light and electron optica, image analysis, and morphometric methods to all research groups within the University of Pittsburgh School of Medicine. Confocal microscopy is an essential service provided by the center, the current core use confocal microscopes within the facility are a 4 yr. old Nikon A1R, two Olympus FV1000's (8 and 10 years old) and a 14 year old Olympus fluoview 500, There is a single prime reason for this application: to provide critically needed instrument time to the NIH supported users of the Center for Biologic Imaging. Since the CBI commenced operations 22 years ago, it has become an integral part of the medical research community currently participating in research projects with more than 300 PHS funded groups within the medical area, as well as in PHS supported projects with investigators in other departments and at neighboring institutions. The PHS funded user base within the institution continues to expand, and a lack of available confocal time has become a major limiting factor in the utility of the center, this leads to considerable frustration amongst users. The acquisition of a basic single photon confocal microscope will be a tremendous addition to the activity and functionality of the center and will help alleviate the current user bottle neck for single photon confocal microscopy.